Friendships positively support healthy socioemotional and cognitive development. Research indicates that friendships often form between people with similar demographic and behavioral characteristics. Understanding and sharing thoughts, feelings and perceptions are essential to a friendship. Such processes are linked to brain activity and structures of the corticolimbic network (CLN), which is associated with perspective-taking, emotion processing and regulation. This study aims to investigate neural and behavioral similarities between friend dyads. T1-neuroimaging, neurophysiological and behavioral data was obtained from 64 healthy adults (50 % female, 32 same-sex friend dyads; age 18-30) and gray matter volume was extracted for the CLN (subcortical: amygdala, hippocampus, nucleus accumbens; neocortical: anterior cingulate, medial orbitofrontal areas) using FreeSurfer. Participants completed questionnaires assessing friendship closeness, physical and mental health, emotion regulation and empathy. Similarity between friend dyads was quantified by correlation coefficients and comparisons to random adult dyads. All adults were significantly similar in respect to the CLN and we did not identify higher similarity in brain structures for friends as compared to random adult dyads. However, friends' CLN similarity was associated with similarity in reported closeness (r=0.38,p=.03). Furthermore, similarity in cognitive emotion regulation was predictive of similarity in the CLN amongst all adults (friends/adults: std.beta=.45/.15; p=.009/.001; R2=.18/.02). Studying friendships can deepen our understanding of the underlying mechanisms of social bonding which are essential for healthy development. We aim to extend our analysis by incorporating functional neuroimaging and network measures. Furthermore, we will assess whether perspective-taking and regulatory skills within friendship networks may link to resilience.